This invention relates generally to power driven tools, and more particularly, to a power driven tool for tightening or loosening fasteners including a ratchet mechanism and an end cap. Examples of power driven ratchet wrenches are disclosed in co-owned U.S. Pat. Nos. 4,821,611 and 8,261,849, which are incorporated by reference.
Although configurations vary, ratchet wrenches usually have a drive element rotatably mounted in a yoke. The drive element is operatively connected to a motor that selectively rotates the drive element to tighten or loosen fasteners. Some of these ratchet wrenches also include an impact mechanism connecting the motor to the drive element that imparts an impact to the drive element under high load conditions such as may occur when a seized fastener is being loosened. The yoke that holds the drive element is formed by a pair of spaced, cantilevered plates or arms. The drive element positioned in the space or opening between the plates usually is exposed around its entire circumferential surface except where the plates connect to the ratchet body.
Frequently, when dirt and debris comes in contact with the exposed surface, the drive element pulls the dirt and debris into the interior of the ratchet wrench. Once inside the wrench, the dirt and debris can cause wear between internal moving parts of the wrench. Worse, the dirt and debris can cause the wrench to jam. Further, under high loads forces inside the wrench can act to spread the plates that form the yoke. Spreading is undesirable. Thus, there is a need for a way to prevent yoke spreading, as well as to guard against dirt and debris entering the wrench.